Semiconductor device having fin structures

ABSTRACT

A semiconductor device structure is provided. The structure includes a semiconductor substrate having a well pick-up region and an active region. Each of the well pick-up region and the active region includes a first well region and a second well region that have different conductivity types. There is a well boundary between the first well region and the second well region. A first fin structure is in the first well region of the well pick-up region and second fin structures are in the first well region of the active region. The minimum distance between the well boundary and the first fin structure is greater than the minimum distance between the well boundary and one of the second fin structures that is closest to the well boundary.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.62/564,391 filed on Sep. 28, 2017, the entirety of which is incorporatedby reference herein.

BACKGROUND

The semiconductor integrated circuit (IC) industry has experienced rapidgrowth. Technological advances in IC materials and design have producedgenerations of ICs where each generation has smaller and more complexcircuits than the previous generation. However, these advances haveincreased the complexity of processing and manufacturing ICs and, forthese advances to be realized, similar developments in IC processing andmanufacturing are needed. In the course of IC evolution, functionaldensity (i.e., the number of interconnected devices per chip area) hasgenerally increased while geometric size (i.e., the smallest componentthat can be created using a fabrication process) has decreased.

As the semiconductor industry has progressed into nanometer technologyprocess nodes in pursuit of higher device density, higher performance,and lower costs, challenges from both fabrication and design issues haveresulted in the development of three-dimensional designs, such as thefin field effect transistor (FinFET). FinFETs are fabricated with a thinvertical “fin” (or fin structure) extending from a substrate. Thechannel of the FinFET is formed in this vertical fin. A gate is providedover the fin. Advantages of the FinFET may include reducing the shortchannel effect and higher current flow.

Although existing FinFETs and methods of fabricating FinFETs have beengenerally adequate for their intended purposes, they have not beenentirely satisfactory in all respects. For example, as the size of thefin (e.g., the fin width) and the fin-to-fin space (i.e., the distancebetween two adjacent fins) are reduced, the resistance of the wellpick-up region is increased due to the interdiffusion between the wellpick-up regions with different conductivity types, and thus theelectrical performance of the semiconductor device is reduced.Therefore, it is a challenge to form reliable semiconductor devices atsmaller and smaller sizes.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It shouldbe noted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is schematic top view showing a semiconductor device with finstructures in accordance with some embodiments.

FIGS. 2A to 2F are schematic top view showing various stages of a methodof forming a semiconductor device with fin structures in accordance withsome embodiments.

FIGS. 3A to 3F are schematic cross-sectional views showing variousstages of the method of forming the semiconductor device with finstructures taken along the line A-A′ in FIGS. 2A to 2F.

FIGS. 4A to 4F are schematic cross-sectional views showing variousstages of the method of forming the semiconductor device with finstructures taken along the line B-B′ in FIGS. 2A to 2F.

FIG. 5 is schematic top view showing a semiconductor device with finstructures in accordance with some embodiments.

FIG. 6 is schematic top view showing a semiconductor device with finstructures in accordance with some embodiments.

FIG. 7 is schematic top view showing a semiconductor device with finstructures in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows includes embodiments in which the first and second features areformed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact.The present disclosure may repeat reference numerals and/or letters insome various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between somevarious embodiments and/or configurations discussed.

Furthermore, spatially relative terms, such as “beneath,” “below,”“lower,” “above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Some embodiments of the disclosure are described. Additional operationscan be provided before, during, and/or after the stages described inthese embodiments. Some of the stages that are described can be replacedor eliminated for different embodiments. Additional features can beadded to the semiconductor device structure. Some of the featuresdescribed below can be replaced or eliminated for different embodiments.Although some embodiments are discussed with operations performed in aparticular order, these operations may be performed in another logicalorder.

The fins may be patterned using any suitable method. For example, thefins may be patterned using one or more photolithography processes,including double-patterning or multi-patterning processes. Generally,double-patterning or multi-patterning processes combine photolithographyand self-aligned processes, allowing patterns to be created that have,for example, pitches smaller than what is otherwise obtainable using asingle, direct photolithography process. For example, in one embodiment,a sacrificial layer is formed over a substrate and patterned using aphotolithography process. Spacers are formed alongside the patternedsacrificial layer using a self-alignment process. The sacrificial layeris then removed, and the remaining spacers may then be used to patternthe fins.

Embodiments of a semiconductor device structure and a method for forminga semiconductor device structure are provided. FIG. 1 is schematic topview showing a semiconductor device 200 with fin structures inaccordance with some embodiments. As shown in FIG. 1, the semiconductordevice 200 includes a semiconductor substrate 100 having a well pick-upregion 10, an active region 30, and a dummy region 20. In someembodiments, the dummy region 20 is between the well pick-up region 10and the active region 30. In some embodiments, the well pick-up region10 includes a first well region 40 having a first conductivity type, asecond well region 50 having an opposite second conductivity typeadjacent to the first well region 40, and a third well region 60 havingthe first conductivity type adjacent to the second well region 50. Thatis, the first well region 40 and the third well region are doped with afirst type of dopants. The second well region 50 is doped with anopposite second type of dopants. Moreover, the dummy region 20 and theactive region 30 also include the first well region 40, the second wellregion 50 adjacent to the first well region 40, and the third wellregion 60 adjacent to the second well region 50, respectively. As aresult, the second well region 50 is between the first well region 40and third well region 60, so that a first well boundary B1 is definedbetween the first well region 40 and the second well region 50 and asecond boundary B2 is defined between the second well region 50 and thethird well region 60. In some embodiments, the first and third wellregions 40 and 60 (e.g., PMOS regions) are used for P-type FinFETsformed thereon and the second region 50 (e.g., an NMOS region) is usedfor N-type FinFETs formed thereon. Alternatively, the first and thirdwell regions 40 and 60 (e.g., NMOS regions) are used for N-type FinFETsformed thereon and the second region 50 (e.g., a PMOS region) is usedfor P-type FinFETs formed thereon.

In some embodiments, the semiconductor substrate 100 includes asemiconductor material (e.g., silicon). In some other embodiments, thesemiconductor substrate 100 may include another elementarysemiconductor, such as germanium; a compound semiconductor includingsilicon carbide, gallium arsenic, gallium phosphide, indium phosphide,indium arsenide, and/or indium antimonide; an alloy semiconductorincluding SiGe, GaAsP, AlInAs, AlGaAs, GalnAs, GaInP, and/or GaInAsP, ora combination thereof. Alternatively, the semiconductor substrate 100 isa semiconductor on insulator (SOD.

In some embodiments, the semiconductor device 200 further includes afirst fin structure 100 a protruding from the semiconductor substrate100 in the first well region 40 of the well pick-up region 10. Moreover,one or more second fin structures 100 b protrude from the semiconductorsubstrate 100 in the first well region 40 of the active region 30 andextend into the first well region 40 of the dummy region 20.

In some embodiments, the first fin structure 100 a is spaced apart fromthe first well boundary B1 by a first distance D1. Moreover, one of thesecond fin structures 100 b that is closest to the first well boundaryB1 is also spaced apart from the first well boundary B1 by a seconddistance D2. The first distance D1 may be a minimum distance between thefirst well boundary B1 and the first fin structure 100 a. For example,the first distance D1 is a distance between a sidewall of the first finstructure 100 a and the first well boundary B1. Similarly, the seconddistance D2 may be a minimum distance between the first well boundary B1and the second fin structure 100 b that is closest to the first wellboundary B1. For example, the second distance D2 is a distance between asidewall of the second fin structure 100 b and the first well boundaryB1. In some embodiments, the ratio of the first distance D1 to thesecond distance D2 is in a range from about 2 to about 3.5. In someembodiments, the first distance D1 is in a range from about 50 nm toabout 70 nm. The second distance D2 is in a range from about 20 nm toabout 25 nm. In some embodiments, the first distance D1 is greater thanthe second distance D2. The sufficient difference between the firstdistance D1 and the second distance D2 is designed to prevent aninterdiffusion region (or referred to as a depletion region that iscaused by doping the first well region 40 and the second well region 50with different types of dopants) (not shown) in the first well region 40from extending into the first fin structure 110 a. As a result, theresistance of the first fin structure 110 a can be prevented from beingincreased. Moreover, the sufficient utilized area of the semiconductorsubstrate 100 for forming the first fin structure 110 a can be obtained,thereby preventing the resistance of the first fin structure 110 a frombeing increased. In some embodiments, the first distance D1 is not lessthan the maximum length of the interdiffusion region in the first wellregion 40.

In some embodiments, the first fin structure 100 a has a first fin widthW1 and each of the second fin structures 100 b has a second fin widthW2. In some embodiments, the ratio of the first fin width W1 to thesecond fin width W2 is in a range from about 2.5 to about 20. In someembodiments, the first fin width W1 is in a range from about 25 nm toabout 100 nm. The second fin width W2 is in a range from about 5 nm toabout 10 nm.

In some embodiments, the second fin width W2 is less than the first finwidth W1. Since the interdiffusion region in the first well region 40may extend into the first fin structure 110 a, the sufficient differencebetween the first fin width W1 and the second fin width W2 is designedto prevent the dopant depletion or dopant lost (which is caused by theinterdiffusion region) in the first fin structure 110 a from beinggreatly increased. As a result, the resistance of the first finstructure 110 a can be prevented from being increased.

In some embodiments, the semiconductor device 200 further includes athird fin structure 100 c protruding from the semiconductor substrate100 in the second well region 50 of the well pick-up region 10.Moreover, one or more fourth fin structures 100 d protrude from thesemiconductor substrate 100 in the second well region 50 of the activeregion 30 and extend into the second well region 50 of the dummy region20.

In some embodiments, the third fin structure 100 c is spaced apart fromthe first well boundary B1 by a third distance D3. Moreover, one of thefourth fin structures 100 d that is closest to the first well boundaryB1 is also spaced apart from the first well boundary B1 by a fourthdistance D4. The third distance D3 may be a minimum distance between thefirst well boundary B1 and the third fin structure 100 c. For example,the third distance D3 is a distance between a sidewall of the third finstructure 100 c and the first well boundary B1. Similarly, the fourthdistance D4 may be a minimum distance between the first well boundary B1and the fourth fin structure 100 d that is closest to the first wellboundary B1. For example, the fourth distance D4 is a distance between asidewall of the fourth fin structures 100 d and the first well boundaryB1. In some embodiments, the ratio of the third distance D3 to thefourth distance D4 is in a range from about 1 to about 2. In someembodiments, the third distance D3 is in a range from about 30 nm toabout 40 nm. The fourth distance D4 is in a range from about 20 nm toabout 30 nm. In some embodiments, the third distance D3 is greater thanthe fourth distance D4. Similarly, the sufficient difference between thethird distance D3 and the fourth distance D4 is designed to prevent aninterdiffusion region (which is caused by doping the first well region40 and the second well region 50 with different types of dopants) (notshown) in the second well region 50 from extending into the third finstructure 110 c. As a result, the resistance of the third fin structure110 c can be prevented from being increased. Moreover, the sufficientutilized area of the semiconductor substrate 100 for forming the thirdfin structure 110 c can be obtained, thereby preventing the resistanceof the third fin structure 110 c from being increased. In someembodiments, the third distance D3 is not less than the maximum lengthof the interdiffusion region in the second well region 50. In someembodiments, the first distance D1 is different from or substantiallyequal to the third distance D3. For example, the first distance D1 isgreater than the third distance D3, as shown in FIG. 1.

In some embodiments, the third fin structure 100 c has a third fin widthW3 and each of the fourth fin structures 100 d has a fourth fin widthW4. In some embodiments, the ratio of the third fin width W3 to thefourth fin width W4 is in a range from about 1.5 to about 10. In someembodiments, the third fin width W3 is in a range from about 12 nm toabout 50 nm. The fourth fin width W4 is in a range from about 5 nm toabout 8 nm. In some embodiments, the fourth fin width W4 is less thanthe third fin width W3. Similarly, since the interdiffusion region inthe second well region 50 may extend into the third fin structure 110 c,the sufficient difference between the third fin width W3 and the fourthfin width W4 is designed to prevent the dopant depletion or dopant lost(which is caused by the interdiffusion region) in the third finstructure 110 c from being greatly increased. As a result, theresistance of the third fin structure 110 c can be prevented from beingincreased. In some embodiments, the first fin width W1 is different fromor substantially equal to the third fin width W3.

In some embodiments, the first fin structure 100 a has a first finlength L1 and the third fin structure 100 c has a second fin length L2that is substantially equal to the first fin length L1. As a result, twoends of the first fin structure 100 a are respectively aligned to twocorresponding ends of the third fin structure 100 c, as shown in FIG. 1.In some embodiments, the first fin length L1 is in a range from about 50nm to about 150 nm and the second fin length L2 is in a range from about50 nm to about 150 nm.

In some embodiments, the semiconductor device 200 further includes afifth fin structure 100 e protruding from the semiconductor substrate100 in the third well region 60 of the well pick-up region 10. Moreover,one or more sixth fin structures 100 f protrude from the semiconductorsubstrate 100 in the third well region 60 of the active region 30 andextend into the third well region 60 of the dummy region 20.

In some embodiments, the fifth fin structure 100 e is spaced apart fromthe second well boundary B2. Moreover, one of the sixth fin structures100 f that is closest to the second well boundary B2 is also spacedapart from the second well boundary B2. The minimum distance (which isreferred to as a fifth distance) between the second well boundary B2 andthe fifth fin structure 100 e may be greater than the minimum distance(which is referred to as a sixth distance) between the second wellboundary B2 and one of the sixth fin structures 100 f that is closest tothe second well boundary B2. The fifth distance may be a distancebetween a sidewall of the fifth fin structure 100 e and the second wellboundary B2. The sixth distance may be a distance between the secondwell boundary B2 and a sidewall of the sixth fin structure 100 f that isclosest to the second well boundary B2. In some embodiments, the ratioof the fifth distance to the sixth distance is the same as or similar tothe ratio of the first distance D1 to the second distance D2. Moreover,the fifth distance is the same as or similar to the first distance D1.The sixth distance is the same as or similar to the second distance D2.Similarly, the sufficient difference between the fifth distance and thesixth distance is designed to prevent an interdiffusion region (which iscaused by doping the second well region 50 and the third well region 60with different types of dopants) (not shown) in the third well region 60from extending into the fifth fin structure 110 e. As a result, theresistance of the fifth fin structure 110 e can be prevented from beingincreased. Moreover, the sufficient utilized area of the semiconductorsubstrate 100 for forming the fifth fin structure 110 e can be obtained,thereby preventing the resistance of the fifth fin structure 110 e frombeing increased. In some embodiments, the fifth distance is not lessthan the maximum length of an interdiffusion region (not shown) in thethird well region 60 caused by doping the second well region 50 and thethird well region 60 with different types of dopants.

In some embodiments, the third fin structure 100 c is spaced apart fromthe second well boundary B2 by a distance that is the same or differentfrom the third distance D3. Moreover, one of the fourth fin structures100 d that is closest to the second well boundary B2 is also spacedapart from the second well boundary B2 by a distance that is the same ordifferent from the fourth distance D4 different from In someembodiments, the minimum distance between the second well boundary B2and the third fin structure 100 c is not less than the maximum length ofan interdiffusion region (not shown) in the second well region 50 causedby doping the second well region 50 and the third well region 60 withdifferent types of dopants.

Moreover, the minimum distance between the second well boundary B2 andthe fifth fin structure 100 e is different from or substantially equalto the minimum distance between the second well boundary B2 and thethird fin structure 100 c. For example, the minimum distance between thesecond well boundary B2 and the fifth fin structure 100 e is greaterthan the minimum distance between the second well boundary B2 and thethird fin structure 100 c, as shown in FIG. 1.

In some embodiments, the fifth fin structure 100 e may have a fin widththat is different from a fin width of each of the sixth fin structures100 f. For an example, the fin width of the fifth fin structure 100 e isthe same as or similar to the first fin width W1 and the fin width ofthe sixth fin structure 100 f is the same as or similar to the secondfin width W2 or the fourth fin width W4. In this case, the fin width ofthe sixth fin structure 100 f is less than the fin width of the fifthfin structure 100 e. In some embodiments, the fin width of the fifth finstructure 100 e is different from or substantially equal to the thirdfin width W3 of the third fin structure 100 c. Similarly, since theinterdiffusion region in the third well region 60 may extend into thefifth fin structure 100 e, the sufficient difference between the fifthfin structure 100 e and sixth fin structure 100 f is designed to preventthe dopant depletion or dopant lost (which is caused by theinterdiffusion region) in the fifth fin structure 100 e from beinggreatly increased. As a result, the resistance of the fifth finstructure 100 e can be prevented from being increased.

In some embodiments, the fifth fin structure 100 e has a fin lengthsubstantially equal to the first fin length L1 of the first finstructure 100 a and the second fin length L2 of the third fin structure100 c. As a result, two ends of the fifth fin structure 100 e arerespectively aligned to two corresponding ends of the first finstructure 100 a and two corresponding ends of the third fin structure100 c.

In some embodiments, the semiconductor device 200 further includesisolation structures may be positioned on opposite sides of the finstructures (e.g., the first, second, third, fourth, fifth, and six finstructures 100 a, 100 b, 100 c, 100 d, 100 e, and 100 f). In someembodiments, each of the isolation structures includes an isolationfeature 120 and a liner structure (not shown) covering the sidewall andthe bottom of the isolation feature 120. As a result, the semiconductorsubstrate 100 and the lower portion of the fin structures (e.g., thefirst, second, third, fourth, fifth, and six fin structures 100 a, 100b, 100 c, 100 d, 100 e, and 100 f) are spaced apart from the isolationfeatures 120 by the liner structures.

In some embodiments, the isolation feature 120 is made of a dielectricmaterial, such as silicon oxide, fluoride-doped silicate glass (FSG), alow-k dielectric material, and/or another suitable insulating material.The isolation features 120 may be shallow trench isolation (STI)features. In some embodiments, the liner structure may include a singlelayer or a multiple structure and may be made of silicon oxide, siliconnitride, silicon oxynitride, silicon carbide (SiC), or a combinationthereof.

In some embodiments, a distance between the sidewall of the first finstructure 100 a and the sidewall of the third fin structure 100 c isgreater than a distance between the sidewall of the second fin structure100 b and the sidewall of the fourth fin structure 100 d. In someembodiments, the first fin structure 100 a and the third fin structure100 c are separated by one of the isolation structures. In those cases,this isolation structure may be in direct contact with both the sidewallof the first fin structure 100 a and the sidewall of the third finstructure 100 c. Similarly, in some embodiments, a distance between thesidewall of the fifth fin structure 100 e and the sidewall of the thirdfin structure 100 c is greater than a distance between the sidewall ofthe sixth fin structure 100 f and the sidewall of the fourth finstructure 100 d. In some embodiments, the fifth fin structure 100 f andthe third fin structure 100 c are separated by one of the isolationstructures. In those cases, this isolation structure may be in directcontact with both the sidewall of the fifth fin structure 100 f and thesidewall of the third fin structure 100 c

In some embodiments, the semiconductor device 200 further includes gatestructures 130 are positioned over the semiconductor substrate 100. Someof those gate structures 130 are across the first, third, and the fifthfin structures 100 a, 100 c, and 100 e in the pick-up region 10.Moreover, the other gate structures 130 are across the second, fourth,and sixth fin structures 100 b, 100 d, and 100 f in the dummy region 50and the second, fourth, and sixth fin structures 100 b, 100 d, and 100 fin the active region 60.

In some embodiments, each of the gate structures 130 may include a gatedielectric layer, a gate electrode layer, and/or one or more additionallayers. In some embodiments, the gate structure 130 is a sacrificialgate structure or a dummy gate structure such as formed in a replacementgate process used to form a metal gate structure. In some embodiments,the gate structure 130 includes polysilicon layer (as the gate electrodelayer). Moreover, the gate dielectric layer of the gate structure 130may include silicon dioxide or another suitable dielectric material.Alternatively, the gate dielectric layer of the gate structure 130 mayinclude a high-k dielectric layer such as HfO₂, TiO₂, HfZrO, Ta₂O₃,HfSiO₄, ZrO₂, ZrSiO₂, or a combination thereof.

In some embodiments, the gate structure 130 may be a metal gatestructure. The metal gate structure may include an interfacial layer, agate dielectric layer, work function layer(s), and a fill metal layer.In some embodiments, the interfacial layer may include a dielectricmaterial such as silicon oxide layer (SiO₂) or silicon oxynitride(SiON). Moreover, an exemplary p-type work function metal may includeTiN, TaN, Ru, Mo, Al, WN, ZrSi₂, MoSi₂, TaSi₂, NiSi₂, WN, or acombination thereof. An exemplary n-type work function metal may includeTi, Ag, TaAl, TaAlC, TiAlN, TaC, TaCN, TaSiN, Mn, Zr, or a combinationthereof.

FIGS. 2A to 2F are schematic top view showing various stages of a methodof forming the semiconductor device 200 shown in FIG. 1, in accordancewith some embodiments. FIGS. 3A to 3F are cross-sectional views alongline A-A′ of FIGS. 2A to 2F to show various stages of a process forforming the semiconductor device 200, in accordance with someembodiments. FIGS. 4A to 4F are cross-sectional views along line B-B′ ofFIGS. 2A to 2F to show various stages of a process for forming thesemiconductor device 200, in accordance with some embodiment.

As shown in FIGS. 2A, 3A, and 4A, a semiconductor substrate 100 isreceived. In some embodiments, the semiconductor substrate 100 includesa semiconductor material (e.g., silicon). In some other embodiments, thesemiconductor substrate 100 may include another elementarysemiconductor, such as germanium; a compound semiconductor includingsilicon carbide, gallium arsenic, gallium phosphide, indium phosphide,indium arsenide, and/or indium antimonide; an alloy semiconductorincluding SiGe, GaAsP, AlInAs, AlGaAs, GalnAs, GaInP, and/or GaInAsP, ora combination thereof. Alternatively, the semiconductor substrate 100 isa semiconductor on insulator (SOI).

In some embodiments, the semiconductor substrate 100 has a well pick-upregion 10, an active region 30, and a dummy region 20 between the wellpick-up region 10 and the active region 30. In some embodiments, thesemiconductor substrate 100 may be doped (e.g. with a P-type dopantand/or an N-type dopant) or undoped. For example, the semiconductorsubstrate 100 is doped with P-type and N-type dopants by wellimplantation processes. Each of the well pick-up region 10, the dummyregion 20, and the active region 30 includes a first well region 40, asecond well region 50, and a third well region 60. Moreover, the firstwell region 40 and the third well region 60 are doped with a first typeof dopants, so that the first well region 40 and the third well region60 have a first conductivity type. The second well region 50 is dopedwith an opposite second type of dopants, so that the second well region50 has an opposite second conductivity type adjacent to the first wellregion 40 and the third well region 60. Therefore, the second wellregion 50 is between the first well region 40 and third well region 60.A first well boundary B1 is between the first well region 40 and thesecond well region 50. Moreover, a second boundary B2 is between thesecond well region 50 and the third well region 60. For an example, thefirst and third well regions 40 and 60 (e.g., PMOS regions) are used forP-type FinFETs formed thereon. Moreover, the second region 50 (e.g., anNMOS region) is used for N-type FinFETs formed thereon.

In some embodiments, in a P-well implantation process for the first andthird well regions 40 and 60, P-type dopants are implanted at an energylevel in a range from about 20K eV to about 40K eV. Moreover, the dopantconcentration of the P-type dopants is in a range from about 1×10¹³atoms/cm³ to about 7×10¹³ atoms/cm³. In some embodiments, N-type dopantsare implanted at an energy level in a range from about 80K eV to about120K eV. Moreover, the dopant concentration of the N-type dopants is ina range from about 1×10¹³ atoms/cm3 to about 6×10¹³ atoms/cm³, in someembodiments.

In some embodiments, the semiconductor substrate 100 has a first region100 a and a second region 100 b adjacent to the first region 100 a. Thefirst region 100 a may be employed to form P-type devices, such asP-type metal-oxide-semiconductor field-effect transistors (MOSFETs). Inthose cases, the second region 100 b may be employed to form N-typedevices, such as N-type MOSFETs. Therefore, the first region 100 a maybe referred to as a PMOS region, and the second region 100 b may bereferred to as an NMOS region. In some other embodiments, P-type devices(or N-type devices) are formed in both the first region 100 a and thesecond region 100 b.

In some embodiments, a first photoresist (not shown) may be formed overthe semiconductor substrate 100 to expose regions where the first andthird well regions 40 and 60 to be formed. Afterwards, a P-wellimplantation process may be performed on the exposed regions of thesemiconductor substrate 100, so as to form the first and third wellregions 40 and 60. Similarly, after removal of the first photoresist, asecond photoresist (not shown) is formed over the semiconductorsubstrate 100 to expose a region where the second well region 50 to beformed. Afterwards, an N-well implantation process is performed on theexposed region of the semiconductor substrate 100 to form the secondwell region 50. In some embodiments, the first and third well regions 40and 60 may be doped with boron (B) ions to form the P-wells. Moreover,the second well region 50 is doped with arsenic (As) or phosphorous (P)ions to form the N-well.

Afterwards, a first masking layer 102 and an overlying second maskinglayer 104 are successively formed over the semiconductor substrate 100for formation of fin structures in subsequent processes. The firstmasking layer 102 may be a buffer layer between semiconductor substrate100 and the second masking layer 104. In some embodiments, the firstmasking layer 102 is formed of silicon oxide. In some embodiments, thesecond masking layer 104 is made of SiN or SiON. In some embodiments,the first masking layer 102 and the overlying second masking layer 104are formed by a respective deposition process. For example, thedeposition process for formation of the first masking layer 102 may be athermal oxidation process. Moreover, the deposition process forformation of the second masking layer 104 may be a chemical vapordeposition (CVD) process, a low-pressure chemical vapor deposition(LPCVD) process, a plasma enhanced chemical vapor deposition (PECVD)process, a high-density plasma chemical vapor deposition (HDPCVD)process, a spin-on process, a sputtering process, or another applicableprocess.

The second masking layer 104 is patterned by patterning a photoresistlayer (not shown) with photolithography and then etching theun-protected second masking layer 104 with an etching process (such as awet etching process or a dry etching process), as shown in FIGS. 2A, 3A,and 4A. The photolithography process includes photoresist coating (e.g.,spin-on coating), soft baking, mask aligning, exposure, post-exposurebaking, developing the photoresist, rinsing and drying (e.g., hardbaking). In some embodiments, after the etching process is performed,the patterned second masking layer 104 include fin patternscorresponding to the active region 30 and those fin patterns extend fromthe active region 30 into the dummy region 20.

As shown in FIGS. 2B, 3B, and 4B, a third masking layer 106 is formed tocover the structure shown in FIGS. 2A, 3A, and 4A, in some embodiments.In some embodiments, the third masking layer 106 is made of photoresistor another suitable masking material. For example, the third maskinglayer 106 is made of photoresist and is patterned by a photolithographyprocess. In some embodiments, after the photolithography process isperformed, the patterned third masking layer 106 includes fin patternscorresponding to the pick-up well region 10. In some embodiments, thefin patterns of the third masking layer 106 shown in FIG. 2B have adifferent width than that of the fin patterns of the second maskinglayer 104 shown in FIG. 2A. Moreover, the minimum distances between thefin patterns of the third masking layer 106 shown in FIG. 2B are alsodifferent from those between the fin patterns of the second maskinglayer 104 shown in FIG. 2A. For example, the fin patterns of the thirdmasking layer 106 shown in FIG. 2B have a width greater than that of thefin patterns of the second masking layer 104 shown in FIG. 2A. Moreover,the minimum distances between the fin patterns of the third maskinglayer 106 shown in FIG. 2B are also greater than those between the finpatterns of the second masking layer 104 shown in FIG. 2A.

As shown in FIGS. 2C, 3C, and 4C, after the third masking layer 106 ispatterned, an etching process (such as a wet etching process or a dryetching process) is performed to remove the second masking layer 104 notcovered by the patterned third masking layer 106. As a result, the finpatterns of the third masking layer 106 are transferred into the secondmasking layer 104. After the etching process is performed, the patternedsecond masking layer 104 includes fin patterns corresponding to the wellpick-up region 10, the dummy region 20, and the active region 30. Thosefin patterns have different widths and different fin-to-fin spaces(i.e., the minimum distance between the fin structures).

After forming the fin patterns in the second masking layer 104 andcorresponding to the well pick-up region 10, the dummy region 20, andthe active region 30, the third masking layer 106 may be removed by asuitable removal process, such as etching or plasma ashing, inaccordance with some embodiments.

Afterwards, an etching process (such as a wet etching process or a dryetching process) is performed to remove the first masking layer 102 notcovered by the patterned second masking layer 104. Therefore, the finpatterns of the second masking layer 104 are transferred into the firstmasking layer 102. After the etching process is performed, the patternedfirst masking layer 102 includes fin patterns corresponding to the wellpick-up region 10, the dummy region 20, and the active region 30. Thosefin patterns have different widths and different fin-to-fin spaces(i.e., the minimum distance between the fin structures), as shown inFIGS. 2D, 3D, and 4D.

As shown in FIGS. 2E, 3E, and 4E, an etching process (such as a dry orwet etching process) is performed on the semiconductor substrate 100exposed from the patterned first masking layer 102 and the overlying andpatterned second masking layer 104, in accordance with some embodiments.As a result, a first fin structure 110 a, second fin structures 100 b, athird fin structure 100 c, fourth fin structures 100 d, a fifth finstructure 100 e, and sixth fin structures 100 f, and trenches 110 areformed. During the etching process, the patterned second masking layer104 may be entirely removed, as shown in FIGS. 2E, 3E, and 4E.

Afterwards, the patterned first masking layer 102 may be removed by asuitable removal process, such as etching or plasma ashing, as shown inFIGS. 2F, 3F, and 4F in accordance with some embodiments. As shown inFIG. 2F, the first fin structure 100 a is formed in the first wellregion 40 of the well pick-up region 10. The second fin structures 100 bare formed in the first well region 40 of the active region 30 andextend into the first well region 40 of the dummy region 20. The thirdfin structure 100 c is formed in the second well region 50 of the wellpick-up region 10. The fourth fin structures 100 d are formed in thesecond well region 50 of the active region 30 and extend into the secondwell region 50 of the dummy region 20. The fifth fin structure 100 e isformed in the third well region 60 of the well pick-up region 10. Thesixth fin structures 100 f are formed in the third well region 60 of theactive region 30 and extend into the third well region 60 of the dummyregion 20.

In some embodiments, a first distance D1 (i.e., the minimum distancebetween the first well boundary B1 and the first fin structure 100 a) isdifferent from a second distance D2 (i.e., the minimum distance betweenthe first well boundary B1 and one of the second fin structures 100 bthat is closest to the first well boundary B1). For example, the firstdistance D1 is greater than the second distance D2. In some embodiments,the first distance D1 is not less than the maximum length of aninterdiffusion region (not shown) in the first well region 40 caused bydoping the first well region 40 and the second well region 50 withdifferent types of dopants. In some embodiments, the first fin structure100 a has a first fin width W1 and each of the second fin structures 100b has a second fin width W2 that is different from the first fin widthW1. For example, the second fin width W2 is less than the first finwidth W1.

In some embodiments, a third distance D3 (i.e., the minimum distancebetween the first well boundary B1 and the third fin structure 100 c) isdifferent from a fourth distance D4 (i.e., the minimum distance betweenthe first well boundary B1 and one of the fourth fin structures 100 dthat is closest to the first well boundary B1). For example, the thirddistance D3 is greater than the fourth distance D4. In some embodiments,the third distance D3 is also not less than the maximum length of aninterdiffusion region (not shown) in the second well region 50 caused bydoping the first well region 40 and the second well region 50 withdifferent types of dopants. In some embodiments, the first distance D1is different from or substantially equal to the third distance D3.

In some embodiments, the third fin structure 100 c has a third fin widthW3 and each of the fourth fin structures 100 d has a fourth fin width W4that is different from the third fin width W3. For example, the fourthfin width W4 is less than the third fin width W3. In some embodiments,the first fin width W1 is different from or substantially equal to thethird fin width W3. Moreover, the second fin width W2 is different fromor substantially equal to the fourth fin width W4.

In some embodiments, the first fin structure 100 a has a first finlength L1 and the third fin structure 100 c has a second fin length L2that is substantially equal to the first fin length L1. As a result, twoends of the first fin structure 100 a are respectively aligned to twocorresponding ends of the third fin structure 100 c.

In some embodiments, the minimum distance between the second wellboundary B2 and the fifth fin structure 100 e may be different from theminimum distance between the second well boundary B2 and one of thesixth fin structures 100 f that is closest to the second well boundaryB2. For example, the minimum distance between the second well boundaryB2 and the fifth fin structure 100 e is greater than the minimumdistance between the second well boundary B2 and one of the sixth finstructures 100 f. In some embodiments, the minimum distance between thesecond well boundary B2 and the fifth fin structure 100 e is not lessthan the maximum length of an interdiffusion region (not shown) in thethird well region 60 caused by doping the second well region 50 and thethird well region 60 with different types of dopants.

In some embodiments, the minimum distance between the second wellboundary B2 and the third fin structure 100 c is different from theminimum distance between the second well boundary B2 and one of thefourth fin structures 100 d that is closest to the second well boundaryB2. For example, the minimum distance between the second well boundaryB2 and the third fin structure 100 c is greater than the minimumdistance between the second well boundary B2 and one of the fourth finstructures 100 d that is closest to the second well boundary B2. In someembodiments, the minimum distance between the second well boundary B2and the third fin structure 100 c is not less than the maximum length ofan interdiffusion region (not shown) in the second well region 50 causedby doping the second well region 50 and the third well region 60 withdifferent types of dopants.

Moreover, the minimum distance between the second well boundary B2 andthe fifth fin structure 100 e is different from or substantially equalto the minimum distance between the second well boundary B2 and thethird fin structure 100 c. For example, the minimum distance between thesecond well boundary B2 and the fifth fin structure 100 e is greaterthan the minimum distance between the second well boundary B2 and thethird fin structure 100 c.

In some embodiments, the fifth fin structure 100 e may have a fin widththat is different from a fin width of each of the sixth fin structures100 f. For example, the fin width of the sixth fin structure 100 f isless than the fin width of the fifth fin structure 100 e. In someembodiments, the fin width of the fifth fin structure 100 e is differentfrom or substantially equal to the third fin width W3 of the third finstructure 100 c.

In some embodiments, the fifth fin structure 100 e has a fin lengthsubstantially equal to the second fin length L2 of the third finstructure 100 c. As a result, two ends of the fifth fin structure 100 eare respectively aligned to two corresponding ends of the third finstructure 100 c.

After the first fin structure 110 a, the second fin structures 100 b,the third fin structure 100 c, the fourth fin structures 100 d, thefifth fin structure 100 e, and the sixth fin structures 100 f areformed, a liner structure (not shown) is conformally formed over thesidewall and the bottom of each trench 110 and covers the fin structures110 a to 110 f. The liner structure may serve as a shallow trenchisolation (STI) liner and a protective layer for the fin structures 110a to 110 f. In some embodiments, the liner structure includes a singlelayer or a multiple structure. For example, the liner structure includesa single layer and is made of silicon oxide (SiO₂), silicon carbide(SiC), silicon nitride (SiN or Si₃N₄), silicon oxynitride (SiON), oranother suitable dielectric material. In some embodiments, the linerstructure is formed by a thermal oxidation process or a depositionprocess including CVD, physical vapor deposition (PVD), atomic layerdeposition (ALD), or the like. An optional rapid thermal treatment maybe performed on the liner structure to improve the film quality.

After the liner structure is formed, an insulating layer (not shown) isformed to cover the fin structures 110 a to 110 f and also fills thetrenches 110 that are covered by the liner structure, in accordance withsome embodiments. The insulating layer may be formed of silicon oxide,silicon nitride, low-k dielectric materials, or a combination thereof,and may be formed by a flowable CVD (FCVD) process. Other insulatingmaterials and/or other formation processes may be used.

After the insulating layer is formed, an anneal process may be performedto cure the insulating layer, in accordance with some embodiments. Theanneal process 144 may include a wet steam anneal, and a subsequent dryanneal process.

Afterwards, the insulating layer and the liner structure over the topsurfaces of the fin structures 110 a to 110 f are removed by aplanarization process. The planarization process may be a chemicalmechanical polish (CMP) process. Afterwards, a portion of the insulatinglayer and a portion of the liner structure are removed to expose theupper portions of the fin structures 100 a, 100 c and 100 e, as shown inFIG. 3F, in accordance with some embodiments. Also, the upper portionsof the fin structures 100 b, 100 d and 100 f, as shown in FIG. 4F. As aresult, isolation features 120 are formed. In some embodiments, theinsulating layer and the liner structure are removed by an etchingprocess such as a dry etching process or a wet etching process, so as toform isolation structures such as shallow trench isolation (STI)structures, as shown in FIGS. 2F, 3F, and 4F, in accordance with someembodiments. In some embodiments, the etching process includes a dryetching process using an etching gas comprising ammonia (e.g. NH₃) andhydrogen fluoride (HF).

Afterwards, gate structures 130 are formed over the fin structures 110 ato 100 f to form the semiconductor device 200, as shown in FIG. 1, inaccordance with some embodiments. In some embodiments, some of thosegate structures 130 are across the first, third, and the fifth finstructures 100 a, 100 c, and 100 e in the pick-up region 10 and theother gate structures 130 are across the second, fourth, and sixth finstructures 100 b, 100 d, and 100 f in the dummy region 50 and thesecond, fourth, and sixth fin structures 100 b, 100 d, and 100 f in theactive region 60.

In some embodiments, each of the gate structures 130 may include a gatedielectric layer, a gate electrode layer, and/or one or more additionallayers. In some embodiments, the gate structure 130 is a dummy gatestructure. In those cases, the gate structure 130 includes polysiliconlayer (as the dummy gate electrode layer). Moreover, the dummy gatedielectric layer of the gate structure 130 may include silicon dioxideor another suitable dielectric material. Alternatively, the dummy gatedielectric layer of the gate structure 130 may include a high-kdielectric layer such as HfO₂, TiO₂, HfZrO, Ta₂O₃, HfSiO₄, ZrO₂, ZrSiO₂,or a combination thereof. The dummy gate dielectric layer may be formedby a deposition process, such as CVD, PVD, ALD, high density plasma CVD(HDPCVD), metal organic CVD (MOCVD), or plasma enhanced CVD (PECVD).Moreover, the dummy gate electrode layer is formed by a depositionprocess, such as CVD, PVD, ALD, HDPCVD, MOCVD, or PECVD.

In some embodiments, the gate structure 130 may be a metal gatestructure. The metal gate structure may include an interfacial layer, agate dielectric layer, work function layer(s), and a fill metal layer.In some embodiments, the interfacial layer may include a dielectricmaterial such as silicon oxide layer (SiO₂) or silicon oxynitride(SiON). Moreover, an exemplary p-type work function metal may includeTiN, TaN, Ru, Mo, Al, WN, ZrSi₂, MoSi₂, TaSi₂, NiSi₂, WN, or acombination thereof. An exemplary n-type work function metal may includeTi, Ag, TaAl, TaAlC, TiAlN, TaC, TaCN, TaSiN, Mn, Zr, or a combinationthereof.

Afterwards, in some embodiments, a gate-last process (sometimes referredto as a replacement gate process) is performed. In the gate-lastprocess, the dummy gate structures are removed to form recesses.Afterwards, in some embodiments, a metal gate structure is formed ineach recess.

In some embodiments, the gate dielectric layer of the metal gatestructure includes silicon oxide, silicon nitride, or a high-kdielectric material including a metal oxide or a silicate of Hf, Al, Zr,La, Mg, Ba, Ti, Pb, or a combination thereof. The formation methods ofgate dielectric layer may include CVD, ALD, PECVD, and the like.

In some embodiments, the gate electrode layer of the metal gatestructure may be made of a metal-containing material such as TiN, TaN,TaC, Co, Ru, Al, combinations thereof, or multi-layers thereof, and maybe formed by, e.g., electroplating, electroless plating, or anothersuitable method.

FIG. 5 is schematic top view showing a semiconductor device 300 with finstructures in accordance with some embodiments. Elements in FIG. 5 thatare the same as those in FIG. 1 are labeled with the same referencenumbers as in FIG. 1 and are not described again for brevity. In someembodiments, the semiconductor device 300 is similar to thesemiconductor device 200 shown in FIG. 1. The difference is two ends ofthe first fin structure 100 a are not aligned to the corresponding endsof the third fin structure 100 c or the corresponding ends of the fifthfin structure 100 e. For an example, two ends of the first fin structure100 a are not aligned to the corresponding ends of the third finstructure 100 c. Moreover, those ends of the first fin structure 100 aare still aligned to the corresponding ends of the fifth fin structure100 e. That is, two ends of the third fin structure 100 c are notaligned to the corresponding ends of the fifth fin structure 100 e. Insome embodiments, the semiconductor device 300 may be fabricated by thesame or similar method shown in FIGS. 2A to 2F, 3A to 3F, and 4A to 4F.

FIG. 6 is schematic top view showing a semiconductor device 400 with finstructures in accordance with some embodiments. Elements in FIG. 6 thatare the same as those in FIG. 1 are labeled with the same referencenumbers as in FIG. 1 and are not described again for brevity. In someembodiments, the semiconductor device 400 is similar to thesemiconductor device 200 shown in FIG. 1. The difference is at least thefirst fin length L1 of the semiconductor device 400 is different fromthe second fin length L2 of the semiconductor device 400. For example,the first fin length L1 is less than the second fin length L2, as shownin FIG. 6. As a result, at least one end of the first fin structure 100a is not aligned to the corresponding end of the third fin structure 100c. Alternatively, the first fin length L1 may be greater than the secondfin length L2. In some embodiments, the semiconductor device 400 may befabricated by the same or similar method shown in FIGS. 2A to 2F, 3A to3F, and 4A to 4F.

FIG. 7 is schematic top view showing a semiconductor device 500 with finstructures in accordance with some embodiments. Elements in FIG. 7 thatare the same as those in FIG. 1 are labeled with the same referencenumbers as in FIG. 1 and are not described again for brevity. In someembodiments, the semiconductor device 500 is similar to thesemiconductor device 200 shown in FIG. 1. A difference is one or morefin structures in the active region 30 may not extend into the dummyregion. For an example, the fourth fin structures 100 d formed in theactive region 30 may not extend into the dummy region 20, as shown inFIG. 7. Another difference is one or more fin structures extending fromthe active region 30 into the dummy region 20 include a discontinuousstructure. For example, each of the sixth fin structures 100 f includesa discontinuous structure, as shown in FIG. 7. In some embodiments, thesemiconductor device 500 may be fabricated by the same or similar methodshown in FIGS. 2A to 2F, 3A to 3F, and 4A to 4F.

Embodiments of a semiconductor device structure and a method for formingthe same are provided. A first fin structure, a third fin structure, anda fifth fin structure are formed in a well pick-up region of thesemiconductor substrate. The first fin structure corresponds to a firstwell region. The third fin structure corresponds to a second well regionand the fifth fin structure corresponds to a third well region. A firstwell boundary is formed between the first well region and the secondwell region. A second well boundary is formed between the second wellregion and the third well region. Second fin structures, fourth finstructures, and sixth fin structures are formed in an active region ofthe semiconductor substrate. The second fin structures correspond to thefirst well region. The fourth fin structures correspond to the secondwell region and the sixth fin structures correspond to the third wellregion. The first fin structure has a greater width than the width ofeach second fin structure. Similarly, the third fin structure has agreater width than the width of each fourth fin structure and the fifthfin structure has a greater width than the width of each sixth finstructure. The minimum distance between the first well boundary and thefirst fin structure is greater than the minimum distance between thefirst well boundary and one of the second fin structures that is closestto the first well boundary. The minimum distance between the first wellboundary and the third fin structure is greater than the minimumdistance between the first well boundary and one of the fourth finstructures that is closest to the first well boundary. Similarly, theminimum distance between the second well boundary and the third finstructure is greater than the minimum distance between the second wellboundary and one of the fourth fin structures that is closest to thesecond well boundary. Similarly, the minimum distance between the secondwell boundary and the fifth fin structure is greater than the minimumdistance between the second well boundary and one of the sixth finstructures that is closest to the second well boundary. In the wellpick-up region, those minimum distances between the first fin structureand the first well boundary, between the third fin structure and thefirst well boundary, between the third fin structure and the second wellboundary, and between the fifth fin structure and the second wellboundary are not less than the maximum length ofinterdiffusion/depletion regions caused by the formation of the first,second, and third well regions.

Moreover, the first fin structure has a fin width greater than the widthof each of the second fin structures. Similarly, the third fin structurehas a fin width greater than the width of each of the fourth finstructures and the fifth fin structure has a fin width greater than thewidth of each of the sixth fin structures.

In some embodiments, in the well pick-up region of the semiconductordevice, the minimum distances between the first fin structure and thefirst well boundary, between the third fin structure and the first wellboundary, between the third fin structure and the second well boundary,and between the fifth fin structure and the second well boundary aredesigned to not less than the maximum length of interdiffusion/depletionregions caused by the formation of the first, second, and third wellregions 40, 50, and 60. Accordingly, the resistance of first, third, andfifth fin structures in the well pick-up region 10 can be reduced whilethe fin-to-fin space in the active region is reduced, and thus theelectrical performance of the semiconductor device is maintained orimproved.

In some embodiments, the widths of the first, third, and fifth finstructures in the well pick-up region of the semiconductor device arerespectively greater than the widths of the second, fourth, and sixthfin structures in the active region of the semiconductor device.Accordingly, the dopant depletion or dopant lost (which is caused by thewell implantation processes) in the first, third, and fifth finstructures in the well pick-up region of the semiconductor device can bemitigated or eliminated. As a result, the resistance of first, third,and fifth fin structures in the well pick-up region can be preventedfrom increasing further while the size (e.g., the width) of finstructures in the active region is reduced. Additionally, as the widthsof the first, third, and fifth fin structures in the well pick-up regionof the semiconductor device are increased, the contact area betweenthose fin structures and the corresponding contact structures (e.g.,contact vias) can be increased, thereby reducing the contact resistance.As a result, voltage drop on the interface between the fin structures inthe well pick-up region and the corresponding contact structures can bemitigated or eliminated.

In some embodiments, a semiconductor device structure is provided. Thesemiconductor device structure includes a semiconductor substrate havinga well pick-up region and an active region. Each of the well pick-upregion and the active region includes a first well region having a firstconductivity type and a second well region having an opposite secondconductivity type adjacent to the first well region, so that a wellboundary is between the first well region and the second well region.The semiconductor device structure further includes a first finstructure is in the first well region of the well pick-up region and aplurality of second fin structures is in the first well region of theactive region. The first fin structure is spaced apart from the wellboundary by a first distance. One of the of second fin structures thatis closest to the well boundary is spaced apart from the well boundaryby a second distance. The first distance is greater than the seconddistance.

In some embodiments, a semiconductor device structure is provided. Thesemiconductor device structure includes a well pick-up region formed ina semiconductor substrate. An active region is formed adjacent to thewell pick-up region in the semiconductor substrate. A first finstructure is formed in a first region of the well pick-up region. Asecond fin structure is formed in a first region of the active region.The first region of the well pick-up region and the first region of theactive region are doped with a first type of dopants. A third finstructure is formed in a second region of the well pick-up region. Afourth fin structure is formed in a second region of the active region.The second region of the well pick-up region and the second region ofthe active region are doped with a second type of dopants. A distancebetween a first sidewall of the first fin structure and a third sidewallof the third fin structure is greater than a distance between a secondsidewall of the second fin structure and a fourth sidewall of the fourthfin structure.

In some embodiments, a semiconductor device structure is provided. Thesemiconductor device structure includes a semiconductor substrate havinga well pick-up region and an active region adjacent to the well pick-upregion. Two first fin structures are formed adjacent to each other inthe well pick-up region and spaced apart by a first distance. Two secondfin structures are formed adjacent to each other in the active regionand spaced apart by a second distance. The two first fin structures havedifferent conductivity types and the two second fin structures havedifferent conductivity types. The first distance is greater than thesecond distance.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A semiconductor device structure, comprising: asemiconductor substrate having a well pick-up region and an activeregion, wherein each of the well pick-up region and the active regioncomprises a first well region having a first conductivity type and asecond well region having an opposite second conductivity type adjacentto the first well region, so that a well boundary is between the firstwell region and the second well region; a first fin structure in thefirst well region of the well pick-up region; and a plurality of secondfin structures in the first well region of the active region, whereinthe first fin structure is spaced apart from the well boundary by afirst distance, one of the plurality of second fin structures that isclosest to the well boundary is spaced apart from the well boundary by asecond distance, and the first distance is greater than the seconddistance.
 2. The semiconductor device structure as claimed in claim 1,wherein the ratio of the first distance to the second distance is in arange from about 2 to about 3.5.
 3. The semiconductor device structureas claimed in claim 1, wherein the first distance is in a range fromabout 50 nm to about 70 nm.
 4. The semiconductor device structure asclaimed in claim 1, wherein the first fin structure has a first finwidth and each of the plurality of second fin structures has a secondfin width that is less than the first fin width.
 5. The semiconductordevice structure as claimed in claim 4, wherein the ratio of the firstfin width to the second fin width is in a range from about 2.5 to about20.
 6. The semiconductor device structure as claimed in claim 1, furthercomprising a plurality of gate structures over the semiconductorsubstrate, wherein the plurality of gate structures is across the firstfin structure and the plurality of second fin structures.
 7. Thesemiconductor device structure as claimed in claim 1, furthercomprising: a third fin structure in the second well region of the wellpick-up region; and a plurality of fourth fin structures in the secondwell region of the active region; wherein the third fin structure isspaced apart from the well boundary by a third distance, one of theplurality of fourth fin structures that is closest to the well boundaryis spaced apart from the well boundary by a fourth distance, and thethird distance is greater than the fourth distance.
 8. The semiconductordevice structure as claimed in claim 7, wherein the ratio of the thirddistance to the fourth distance is in a range from about 1 to about 2.9. The semiconductor device structure as claimed in claim 7, wherein thethird fin structure has a third fin width and each of the plurality offourth fin structures has a fourth fin width that is less than the thirdfin width.
 10. A semiconductor device structure, comprising: a wellpick-up region formed in a semiconductor substrate; an active regionformed adjacent to the well pick-up region in the semiconductorsubstrate; a first fin structure formed in a first region of the wellpick-up region; a second fin structure formed in a first region of theactive region, wherein the first region of the well pick-up region andthe first region of the active region are doped with a first type ofdopants; a third fin structure formed in a second region of the wellpick-up region; and a fourth fin structure formed in a second region ofthe active region, wherein the second region of the well pick-up regionand the second region of the active region are doped with a second typeof dopants, wherein a distance between a first sidewall of the first finstructure and a third sidewall of the third fin structure is greaterthan a distance between a second sidewall of the second fin structureand a fourth sidewall of the fourth fin structure.
 11. The semiconductordevice structure as claimed in claim 10, wherein the first fin structureand the third fin structure are separated by an isolation structure. 12.The semiconductor device structure as claimed in claim 11, wherein theisolation structure is in direct contact with both the first sidewall ofthe first fin structure and the third sidewall of the third finstructure.
 13. The semiconductor device structure as claimed in claim10, wherein the first fin structure has a first fin width and the secondfin structure has a second fin width that is less than the first finwidth.
 14. The semiconductor device structure as claimed in claim 13,wherein the third fin structure has a third fin width that is less thanthe first fin width and greater than the second fin width.
 15. Thesemiconductor device structure as claimed in claim 10, furthercomprising: a dummy region formed in the semiconductor substrate andbetween the well pick-up region and the active region, wherein thesecond fin structure extends into a first region of the dummy region.16. The semiconductor device structure as claimed in claim 10, furthercomprising a plurality of gate structures over the semiconductorsubstrate, wherein the plurality of gate structures are respectivelyacross the first, second, the third, and the fourth fin structures. 17.A semiconductor device structure, comprising: a semiconductor substratehaving a well pick-up region and an active region adjacent to the wellpick-up region; two first fin structures formed adjacent to each otherin the well pick-up region, and spaced apart by a first distance; andtwo second fin structures formed adjacent to each other in the activeregion and spaced apart by a second distance, wherein the two first finstructures have different conductivity types and the two second finstructures have different conductivity types, and wherein the firstdistance is greater than the second distance.
 18. The semiconductordevice structure as claimed in claim 17, wherein the first finstructures have a first fin width and the second fin structures have asecond fin width that is less than the first fin width.
 19. Thesemiconductor device structure as claimed in claim 17, wherein the firstfin structures have different lengths, and wherein at least one of thetwo second fin structures comprises a discontinuous structure.
 20. Thesemiconductor device structure as claimed in claim 17, furthercomprising: a third fin structure formed in the well pick-up region andadjacent to one of the two first fin structures, wherein the third finstructure and is separated from the adjacent first fin structure by thefirst distance, and wherein the third fin structure and the adjacentfirst fin structure have different conductivity types.